1. Field of the Invention
This disclosure relates to servicing a wellbore. More specifically, it relates to servicing a wellbore with compositions comprising (i) an acid and/or an acid precursor and (ii) a mutual solvent precursor.
2. Background of the Invention
Natural resources such as gas, oil, and water residing in a subterranean formation can be recovered by drilling wells into the formation. Well drilling involves drilling a wellbore down to the formation while circulating a drilling fluid or mud through the wellbore. Various types of drilling fluids, also known as drill-in fluids when used in the productive interval, have been used in well drilling, such as water-based fluids, mineral oil-based fluids, and synthetic oil-based fluids. Such drilling fluids form a thin, slick filter cake on the formation face that provides for successful drilling of the wellbore and that helps prevent loss of fluid to the subterranean formation.
In well drilling, several stages may be used to produce oil found in subterranean formations. The first stage, which is known as the primary production stage, allows the oil to flow into a production well (or wells) under natural forces. At first, the natural forces may be sufficient to drive the oil to the surface where it is recovered. However, at some point, pumps may be required to displace the oil from the wellbore to the surface. A secondary recovery operation thus is typically performed to recover additional amounts of the oil from the reservoir. A common secondary recovery operation known as secondary flooding involves injecting a fluid such as water into a so-called injection well (or wells) to drive oil in the formation to the production well (or wells). Tertiary recovery operations such as tertiary flooding may also be used to drive the remaining oil from the formation to the production well.
Typically, the presence of the filter cake on the face of the subterranean formation can adversely affect the flow of fluid though the injection wells and the production wells. In the case of the injection wells, particularly in deepwater environments, the injected fluid is not flowed back to remove the filter cake left by the drill-in fluid. The pump pressures (e.g., fracturing pressures) required to inject past the filter cake are higher than desirable for achieving good sweep efficiency of the oil. Thus, it would be desirable to develop improved compositions and methods for removing a filter cake from a subterranean formation.